Mustelid herpesvirus-2, a novel herpes infection in northern sea otters (Enhydra lutris kenyoni).

Oral ulcerations and plaques with epithelial eosinophilic intranuclear inclusions were observed in northern sea otters (Enhydra lutris kenyoni) that died or were admitted for rehabilitation after the 1989 Exxon Valdez oil spill (EVOS) in Alaska, USA. Transmission electron microscopy demonstrated the presence of herpesviral virions. Additionally, a serologic study from 2004 to 2005 found a high prevalence of exposure to a herpesvirus in live-captured otters. Tissues from 29 otters after the EVOS and nasal swabs from 83 live-captured otters in the Kodiak Archipelago were tested for herpesviral DNA. Analysis identified a novel herpesvirus in the gamma subfamily, most closely related to Mustelid herpesvirus-1 from badgers. Results indicated that this herpesvirus is associated with ulcerative lesions but is also commonly found in secretions of healthy northern sea otters.

Major pathologic findings and probable causes of mortality in bottlenose dolphins stranded in South Carolina from 1993 to 2006.

Although cause-of-death information on bottlenose dolphins (Tursiops truncatus) can be located in the literature, few citations include mortality data over a long period of time covering a broad geographic region. This study describes major pathologic findings and probable causes of death of bottlenose dolphins over a 14-yr period (1993-2006) for the coastal region of South Carolina. Probable causes of death for 97 cases were determined based on gross pathology and histopathology. In an additional 30 cases, probable cause of death was apparent from gross pathology alone, and carcass condition precluded histopathology. Of the 97 dolphins examined grossly and histologically, 30 (31%) likely died of infectious disease and 46 (47%) of noninfectious disease; the cause of death was unknown in 21 (22%). Bacterial infections accounted for the large majority of fatal infections and emaciation was the leading cause of noninfectious mortality. Twelve dolphins were killed by human interactions. Of the 30 dolphins diagnosed from gross examination alone, 23 likely died from human interaction and seven were killed by stingray-spine inflictions. Although the absence of consistent use of microbiology, biotoxin analysis and contaminant testing decreases the conclusiveness of the findings, this study has broad implications in establishing baseline data on causes of death of bottlenose dolphins for future studies and for the detection of emerging diseases.

Infection with a novel gammaherpesvirus in northern elephant seals (Mirounga angustirostris).

Twenty juvenile northern elephant seals (Mirounga angustirostris) that died between 1998 and 2004 had ulcers on the tongue, palatine mucosa, and/or tonsils. Histologic examination of the lesions revealed cytoplasmic swelling, nuclear pyknosis, and eosinophilic to amphophilic intranuclear inclusions bodies suggestive of herpesviral infection. Electron microscopic examination and polymerase chain reaction analysis confirmed the presence of a herpesvirus. Subsequent DNA sequencing identified this to be a new gammaherpesvirus that was similar to Porcine lymphotropic virus 2, Alcephaline herpesvirus 1 (malignant catarrhal fever virus from wildebeest), and Chlorocebus rhadinovirus 1 from African green monkeys. Identical herpesviral DNA was also detected in blood and mucosal swabs collected from five healthy elephant seal pups.

Retrospective differentiation of canine distemper virus and phocine distemper virus in phocids.

Formalin-fixed paraffin-embedded tissues from one Caspian seal (Phoca caspica), one harp seal (Phoca groenlandica), one hooded seal (Cystophora cristata), and one harbor seal (Phoca vitulina vitulina) were used to compare the utility of immunohistochemistry (IHC) versus that of a novel seminested reverse transcriptase polymerase chain reaction (RT-PCR) to detect and differentiate canine distemper virus (CDV) and phocine distemper virus (PDV). Four antibodies made against PDV were able to detect both viruses. Two antibodies made against cetacean morbillivirus (CMV) did not label antigens from either CDV or PDV. A third anti-CMV antibody inconsistently stained CDV antigens but did not label PDV antigens. The seminested RT-PCR was able to detect RNA of the phosphoprotein gene in all positive cases. Nucleotide sequence analyses of seminested RT-PCR products were used to differentiate CDV RNA from PDV RNA. From these data, it was determined that IHC using antibodies generated against PDV provided a rapid means of detection for both CDV and PDV antigens; however, differentiation between CDV and PDV was achieved only with the RT-PCR assay.

Meningoencephalitis in two stranded California sea lions (Zalophus californianus) caused by aberrant trematode migration.

Meningoencephalitis caused by aberrant trematode migration is described in two California sea lions (Zalophus californianus) admitted to a rehabilitation hospital between May and August 2001. Both animals displayed seizure activity and were euthanized due to poor response to therapy. Gross abnormal findings included liver flukes (Zalophotrema hepaticum) in the bile ducts and areas of swelling and necrosis in the cerebrum, cerebellum, and brain stem. Histopathology revealed meningoencephalitis with necrosis, hemorrhage, and many trematode eggs within the brain. In one sea lion, an adult trematode was found on the surface of the cerebrum. These are believed to be the first reported cases of meningoencephalitis caused by aberrant trematode migration in pinnipeds.

Cancer in wildlife, a case study: beluga from the St. Lawrence estuary, Québec, Canada.

A population of approximately 650 beluga (Delphinapterus leucas) inhabits a short segment of the St. Lawrence estuary (SLE). Over 17 years (1983-1999), we have examined 129 (or 49%) of 263 SLE beluga carcasses reported stranded. The major primary causes of death were respiratory and gastrointestinal infections with metazoan parasites (22%), cancer (18%), and bacterial, viral, and protozoan infections (17%). We observed cancer in 27% of examined adult animals found dead, a percentage similar to that found in humans. The estimated annual rate (AR) of all cancer types (163/100,000 animals) is much higher than that reported for any other population of cetacean and is similar to that of humans and to that of hospitalized cats and cattle. The AR of cancer of the proximal intestine, a minimum figure of 63 per 100,000 animals, is much higher than that observed in domestic animals and humans, except in sheep in certain parts of the world, where environmental contaminants are believed to be involved in the etiology of this condition. SLE beluga and their environment are contaminated by polycyclic aromatic hydrocarbons (PAHs) produced by the local aluminum smelters. The human population living in proximity of the SLE beluga habitat is affected by rates of cancer higher than those found in people in the rest of Québec and Canada, and some of these cancers have been epidemiologically related to PAHs. Considered with the above observations, the exposure of SLE beluga to PAHs and their contamination by these compounds are consistent with the hypothesis that PAHs are involved in the etiology of cancer in these animals.